In her article, “When Default Cleanup Levels Threaten Redevelopment: A Case for Site-Specific Risk Assessment,” Lisa Smith explains how evaluating actual site conditions can help project teams.
Smith, a Senior Technical Advisor and SCS Engineers’ National Expert in risk mitigation and risk assessment in corrective action, examines a 66-acre residential redevelopment where a site-specific approach saved the developer more than $5 million in remediation costs.
Arsenic concentrations at the property exceeded the default residential risk-based screening level. Using that screening value as the final cleanup endpoint would have required widespread soil removal and replacement with clean fill, potentially making the development economically unworkable.
Instead, SCS Engineers evaluated the property’s planned, enforceable future-use conditions and developed site-specific cleanup target levels. The resulting strategy achieved regulatory closure while maintaining required human health protections.
Jump to read “When Default Cleanup Levels Threaten Redevelopment: A Case for Site-Specific Risk Assessment”
The case illustrates a distinction that matters for property owners and developers: screening levels are tools for identifying potential concerns, but they are not necessarily the appropriate cleanup endpoint for every site.
Default screening levels use standardized, conservative assumptions about exposure. A site-specific evaluation considers whether those assumptions match how people will actually occupy and use the property. In this project, enforceable occupancy conditions and differences in anticipated soil contact supported a more tailored cleanup strategy.
Smith also addresses the practical considerations behind this approach. Developing alternative cleanup levels requires technical evidence, regulatory coordination, time, and investment. The overseeing agency must have authority to approve them, and any conditions supporting the analysis must remain enforceable.
Not every property is a suitable candidate. Complex contamination, uncertain future uses, or limitations on long-term controls may require a different strategy.
For redevelopment teams, the starting point is straightforward: ask whether the default assumptions fit before committing to a remedy based on them.
Read Smith’s full article for the project details, factors that determine whether site-specific cleanup levels are worth pursuing, and questions to discuss with your environmental consultant.
A better understanding of risk can support a more appropriate remedy—and help preserve redevelopment opportunities without compromising human health protection.
Read “When Default Cleanup Levels Threaten Redevelopment: A Case for Site-Specific Risk Assessment”
Reminder: EPA Releases FY2027 Brownfields Grant Guidelines: What Communities Need to Know
Cooling systems are essential to preserving reliable data center operations, but they can require significant amounts of electricity and water, particularly at large facilities. In some regions, competition for available water resources and limitations on existing infrastructure are creating additional challenges for developers. As a result, the industry is increasingly exploring alternative cooling technologies that can reduce operating costs, conserve water, and provide sustained reliability.
Flooded underground mines, once considered liabilities, may afford valuable hydro-geothermal infrastructure and sustainable liquid cooling for the rapidly expanding data center industry. With a specialized technical evaluation, these sites could provide an alternative cooling solution while creating new opportunities for mine owners and surrounding communities.
Extracting New Value from Existing Resources for Data Centers
This latent resource constitutes a vast network found throughout the United States. Many former coal, limestone, and other underground mining operations are naturally flooded after mining activities cease. These “wet” mines can contain substantial volumes of groundwater, or pools, that maintain relatively stable temperatures throughout the year.
By using engineered heat exchange systems, data centers may be able to transfer excess heat into underground mine pools rather than relying entirely on conventional cooling towers or mechanical refrigeration. Depending on site conditions and system design, this approach could reduce freshwater consumption, lower energy requirements, and provide a beneficial use for existing underground infrastructure that might otherwise remain unused.
The concept is already gaining attention. Iron Mountain’s underground data center facility in Pennsylvania shows the potential of using underground water resources to support data center cooling, while projects in Virginia are evaluating the feasibility of using flooded coal mines as thermal resources for proposed data center developments.
Innovative applications, such as Iron Mountain, highlight an emerging opportunity to repurpose former mining operations to support modern infrastructure. However, not every flooded mine will be suitable.
Environmental engineers and hydrogeologists, like SCS, evaluate factors such as groundwater availability, mine geometry, water chemistry, hydraulic connectivity, geological stability, and the surrounding rock and groundwater system’s ability to absorb and dissipate heat. Understanding these underground conditions is critical to determining whether flooded mines can provide a technically feasible, economically practical, and sustainable cooling solution.
Evaluating Mine Water Cooling Potential
SCS Engineers’ mining team is uniquely positioned to help municipalities, data center developers, mine owners, and energy providers assess these opportunities. Our experience in mining, geology, hydrogeology, subsurface characterization, groundwater modeling, drilling, and water management enables us to support investigating projects from initial feasibility through implementation.
Professionals at SCS Engineers recommend starting with an evaluation that covers:
To assess the potential of this sustainable solution, the evaluation results provide detailed intelligence on underground conditions, available water, and long-term thermal performance, which is essential to guide decision-making and infrastructure investment.
Additional Mining and Data Center Resources:
Please join SCS Engineers in congratulating three outstanding colleagues being honored at SWANA RCon this year: Michelle Leonard, Pete Carrico, and Eric Peterson.
Michelle Leonard, Senior Vice President and National Expert in Solid Waste Planning, Recycling, and Sustainable Materials Management, will receive SWANA’s Robert L. Lawrence Distinguished Service Award, the association’s highest individual honor. Michelle’s career reflects decades of leadership in recycling, organics diversion, sustainable materials management, mentorship, and professional service.
Pete Carrico, Senior Vice President and Business Unit Director of SCS Field Services, will receive the SWANA Landfill Gas and Biogas Division Hall of Flame Award, recognizing more than 40 years of sustained contributions to landfill gas systems, operations, monitoring, troubleshooting, safety, and industry education.
Eric Peterson, PE, Vice President and Director of SCS Engineers’ Medford, New Jersey office, will receive the SWANA Landfill Gas & Biogas Technical Division Distinguished Individual Achievement Award for his long-term service, technical leadership, landfill gas recovery expertise, renewable energy work, and commitment to mentoring the next generation of professionals.
These honors reflect the depth of talent, service, and innovation across SCS Engineers and our continued commitment to helping communities and clients advance practical, sustainable solutions in solid waste, recycling, landfill gas, biogas, and resource management.
Congratulations, Michelle, Pete, and Eric. We are proud to celebrate your well-earned recognition and your lasting impact on SWANA, SCS Engineers, our clients, and the solid waste and recycling industry.
With the publication of new landfill rules, landfill management is shifting from periodic compliance using decades-old technology to more rigorous methane management using the newest monitoring technologies. Landfill operations must quantify emissions, install new or upgrade existing gas control systems, monitor using ground-based and remote methods, make repairs more quickly, and maintain audit-ready records.
SCS Engineers, North America’s most recognized landfill service provider, publishes technical bulletins that summarize each rulemaking to highlight the most significant factors that will affect landfill operators.
You will find these publications below, along with our recommendations for identifying and addressing the requirements a landfill must meet to comply with the new standards. By clicking the underlined jurisdiction, you will be directed to more detailed information on the rules.
If you have not already done so, SCS recommends a gap analysis to outline the operational, monitoring, design/construction, and technological changes landfill operators face. The results will support a compliance roadmap: emissions modeling, GCCS capacity review, necessary system upgrades, corrective actions, remote monitoring readiness, leak response staffing, digital recordkeeping, capital budgeting, and site-specific deadlines by jurisdiction.
California: Prepare for faster plume response, including investigation and repair of methane plumes detected by CARB-approved remote sensing technologies, and required monitoring of unsafe-to-walk areas using new technologies.
Maintain rapid repair workflows: for example, the current LMR requires that exceedances be remediated and re-monitored within 10 calendar days, whereas the new standard requires corrective action to begin within 3 calendar days.
Verify that all control devices can meet the 99% methane destruction efficiency standard, with annual source testing and recordkeeping, not just flares.
Plan for increased stringency in almost every aspect of the new rule.
Colorado: Align landfill compliance programs with Regulation 31, Control of Methane Emissions from Municipal Solid Waste Landfills, effective February 14, 2026.
Prepare for waste-in-place/GCCS determinations, gas collection and control requirements, surface emissions monitoring, remote methane monitoring, cover requirements, recordkeeping/reporting, and test-method compliance.
Canada: Determine applicability, calculate annual methane generation with ECCC’s Landfill Methane Modelling Tool, and prepare Methane Generation Assessment Reports; additional requirements apply to emissions above 664 tonnes/year for open landfills and 1,000 tonnes/year for closed landfills.
Plan for new gas systems or upgrades to existing systems by the deadline: 2028 for ≥1,000 tonnes/year with existing recovery systems; 2029 for ≥1,000 tonnes/year without recovery systems; and 2035 for 664–1,000 tonnes/year sites.
States Actively Considering or Developing New Rules
Across North America, we urge operators to build a compliance roadmap now. Stricter rules are in effect in Canada, Colorado, California, Oregon, Washington, and Maryland. They are under consideration in many more states, including Illinois, Michigan, New Mexico, New York, North Carolina, Pennsylvania, and Virginia.
Additional Resources:
Landfills do not stand still. Waste placement changes site conditions every day; infrastructure ages; regulations evolve; and nearby communities expect operators to manage odors, emissions, traffic, and long-term site performance responsibly. Without a clear master plan, landfill owners can find themselves reacting to urgent problems instead of making phased, cost-effective decisions.
That is why landfill master planning is more than an engineering exercise. It is a business discipline. A strong plan brings together airspace management, cell development, permitting, stormwater, leachate, landfill gas systems, closure and post-closure obligations, capital planning, and operations into one practical roadmap.
What a Master Plan Helps Operators See
The value of master planning starts with visibility. Operators need to know how much airspace remains, when the next cell must be designed and permitted, whether existing infrastructure can support future filling, and how regulatory requirements may affect near- and long-term spending. When that information is organized in one place, decision-makers can plan ahead rather than scramble when capacity, compliance, or equipment issues become urgent.
The same discipline applies to landfill gas systems. Gas collection infrastructure must keep pace with waste placement, settlement, liquids, flare capacity, energy recovery opportunities, and changing emissions rules. A landfill gas master plan helps answer a simple but important question: will the system be ready for the next decade?
Planning Turns Risk into Action
The best plans do not sit on a shelf. They help landfill teams prioritize projects, sequence capital investments, anticipate permitting timelines, and coordinate engineering with daily operations. They also support a clearer financial strategy for closure, post-closure care, equipment replacement, regulatory compliance, odor control, emissions management, and community relations.
For owners and operators, the takeaway is straightforward: proactive planning protects site life, reduces surprises, and gives teams more control over technical, regulatory, and financial decisions. The earlier planning begins—and the more consistently it is updated—the better prepared a site will be for what comes next.
Read the Full Article
For a deeper look at landfill master planning, landfill gas system planning, modeling, liquids management, flares, permitting, and long-term budgeting, read the full article “Why Landfill Master Planning Is Essential for Long-Term Site Performance” and explore the related solid waste planning resources below.
Additional Solid Waste and Landfill Master Planning Resources:
SCS Engineers is proud to announce that Eric Peterson, PE, Vice President and Director of the firm’s Medford, New Jersey office, will be honored with the SWANA Landfill Gas & Biogas Technical Division Distinguished Individual Achievement Award at RCon in September.
The award recognizes long-term service to the landfill gas and biogas industry, contributions to SWANA’s mission of transforming waste into a resource, service to the Landfill Gas & Biogas Technical Division, and meaningful contributions to one’s employer and the broader solid waste management field.
Eric said. “I am delighted and honored to receive this recognition from SWANA for my 40-plus years in the landfill gas industry. I’ve enjoyed working in this multifaceted industry, which has afforded me the opportunity to advance practical solutions for methane migration, fugitive emissions, odor control, energy recovery, and public health and safety. The vibrant SWANA landfill gas division has also been a great resource for collaboration and camaraderie.”
Peterson has spent his career helping landfill owners and operators turn environmental challenges into practical, economically viable clean-energy and compliance solutions. His work includes the design of more than 200 landfill gas recovery and control systems; technical and financial due diligence for renewable natural gas and energy projects; methane mitigation, odor control, and hydrogen sulfide treatment; and strategies for managing deep and high-liquid landfills.
“Eric represents the best of SCS Engineers and the landfill gas profession,” said SCS CEO Doug Doerr. “He combines deep technical knowledge with a practical understanding of what facility owners, communities, regulators, and clean-energy investors need to succeed. His work has helped make landfill gas recovery more reliable, more affordable, and more valuable as a renewable energy resource.”
A longtime contributor to SWANA, Peterson has supported the organization through technical education, chapter leadership, committee participation, and landfill gas training. He has helped develop and share best practices that improve gas-capture efficiency, strengthen compliance, and advance the industry’s ability to convert waste-generated methane into usable energy.
Peterson’s influence also extends internationally. He has presented at seminars and conferences supporting landfill gas, biogas, and emissions management in multiple countries. He has helped apply U.S. regulatory and engineering expertise to international landfill emissions programs.
At SCS, Peterson has played a key role in standardizing landfill gas technical practices across the firm, mentoring emerging engineers and scientists, and expanding the company’s landfill gas, biogas, odor control, renewable energy, and due diligence services. Colleagues describe him as a careful listener, thoughtful collaborator, and steady technical leader whose mentorship has helped shape the next generation of environmental professionals.
Please join us in congratulating Eric on this well-deserved honor and thanking him for his lasting contributions to SCS Engineers, SWANA, and the landfill gas and biogas industry.
Senior Vice President Pat Sullivan announces a key leadership transition; Vidhya Viswanathan, previously SCS’s Director of Engineering in the Southwest, now assumes responsibility for the strategic direction and operational oversight of the Solid Waste Group, including the Engineering, Sustainable Materials Management, and Permitting and Compliance teams.
Vidhya has significantly advanced SCS’s solid waste engineering operations across the Southwest and influenced industry standards nationwide. Her leadership in technical areas like landfill gas engineering and composting demonstrates her exceptional expertise and dedication.
Vidhya began her career with the City of Lawton, Oklahoma, joining SCS in 2012 as a Young Professional and recognized regionally and nationally with prestigious awards. Now an SCS mentor with 20 years of experience in the solid waste and environmental consulting industry, she shares her knowledge and skills with young staff members as she progresses through leadership roles at SCS, including Senior Vice President and SCS Board Member. She is a licensed Professional Engineer in California, Arizona, Nevada, and Oklahoma and is based in SCS’s San Diego office.
Vidhya exemplifies the next generation of SCS leadership, combining strong technical expertise, a commitment to quality, and a proven ability to develop teams and deliver exceptional client service. Her vision and leadership are poised to enhance our service offerings, strengthen industry collaborations, and support SCS’s continued top ranking by ENR in the Waste Management industry.
Please join SCS in congratulating Vidhya on her promotion and new leadership role. We look forward to her guiding strategic initiatives that will advance our industry expertise and client solutions in the coming years.
SCS Engineers announces two leadership changes in its Southwest solid waste and engineering divisions. The firm promotes Eric Sonsthagen, P.E., to Project Director and Engineering Lead. After a transition period from Srividhya (Vidhya) Viswanathan, P.E., to Eric, Vidhya will lead the solid waste group.
As part of the Southwestern Business Unit’s broader leadership plan, SCS Engineers will transition several senior roles over the next 18 months to support the next generation of company leaders. Senior Vice President Patrick S. Sullivan, REPA, CPP, BCES, said the company designed these transitions to position SCS and its clients for continued growth and long-term success.
Eric Sonsthagen brings two decades of experience leading environmental and solid waste projects for public and private clients. He designs, reviews, and permits solid waste facilities; oversees landfill gas control and mitigation systems; modifies gas collection and control systems; and manages landfill cell construction and closure projects.
As Project Director and Engineering Lead, Sonsthagen will work across SCS’s specialty business divisions, drive project execution, strengthen the engineering division, and advance strategic priorities. He adds deep expertise in landfill gas engineering and modeling, beneficial reuse evaluations, air permitting, emissions inventories, compliance evaluations, and environmental investigations.
Vidhya Viswanathan currently serves as Senior Vice President and Director of Engineering for SCS Engineers’ Southwest region and will assume leadership of the solid waste group. She has more than two decades of experience in solid waste management, landfill gas engineering, and compost facility design. She is a licensed Professional Engineer in California, Arizona, Nevada, and Oklahoma and is based in San Diego, CA.
“These are important leadership transitions for the next generation of SCS leaders and to assure continued quality delivery for our clients,” Sullivan said.
Eric and Vidhya are both available by contacting SCS Engineers and on LinkedIn.
The California Air Resources Board (CARB) is amending its Landfill Methane Regulation (LMR) to strengthen landfill compliance and meet the state’s target of reducing methane emissions by 40% by 2030. The rules target steep emissions reductions through enhanced surface monitoring, including drone-mounted scanners, robotic sensors, and remote monitoring, as well as stricter wellhead thresholds, among other measures.
The CARB-proposed amendments will have significant impacts on landfill and gas collection and control systems (GCCS), for which owners and operators will need to plan and implement to meet the requirements. As the nation’s top engineering specialist firm in this sector (ENR Solid Waste and Environmental Sourcebook), SCS Engineers has prepared articles and videos to assist landfill owners/operators in complying with these new requirements, including proactive measures that can be deployed to minimize impacts, planning for additional staffing support to complete all of the new monitoring, new or modified GCCS equipment and other infrastructure that will be needed, and new technology necessary to meet new deadlines.
As essential services, or any business for that matter, the changes require additional budget and capital investment to meet extensive surface and leak-monitoring and repair protocols, tighter regulatory timelines for installing GCCS, and more frequent and extensive monitoring and analysis of cover integrity, temperature, oxygen, and liquid levels.
Planning begins now.
SCS’s first article summarizes the key changes and highlights the most salient points of the revised LMR. The companion educational video and slide set are available free of charge to the public and can serve as a starting point for owners, operators, compliance staff, field technicians, and engineers in landfill and gas management, including energy recovery and renewable natural gas facilities.
CARB Landfill Methane Regulations Free Resources:
As demand for securing domestic sources of critical minerals grows, mapping and quantifying their geologic sources is more important than ever. These critical minerals often escaped notice during historical exploration because attention was focused on commodity metals (e.g., gold, silver, copper), and their concentrations are often significantly lower than those of the precious metals. Exploratory drilling can help significantly close the gap in critical mineral data scarcity across the nation, reducing risk from both technoeconomic and environmental standpoints.
Let’s look at a project in Missouri. The Missouri Geological Survey has expanded its efforts to better understand the subsurface geology as it evaluates formations that may contain rare-earth elements and other strategic resources. These broader state efforts reflect a growing nationwide focus on geologic mapping, core preservation, and resource evaluation to find and quantify critical minerals in the U.S.
Our SCS Critical Minerals team, along with HAD, Inc. drillers, recently supported one of these efforts through deep bedrock coring designed to collect high-quality, continuous core for geologic characterization, resource assessment, and long-term archival use. The work included coordinating safe drilling operations, overseeing continuous core recovery, and supporting lithologic logging and field documentation.
The SCS team helps extract reliable subsurface data from deep bedrock intervals, including dolomitic units and underlying Precambrian formations, strengthening our understanding of mineralization potential and the geology of the Viburnum Trend. Data from this drill core will help to identify what critical minerals may be present, how they occur, and in what concentrations– all of which are essential to evaluate their potential for recovery and utilization.
The Missouri Geological Survey will analyze each core for critical mineral and rare-earth element concentrations using a suite of analytical tools, including x-ray fluorescence (XRF) scanning and other geochemical characterization methods. These data will help researchers better understand what elements are present, how concentrations vary with depth and geology, and how mineralization occurs within the subsurface.
Projects like this highlight the value of integrating drilling, coordination, geologic interpretation, and resource-focused evaluation into a single, well-executed field program that can be recreated across the U.S. As public and private stakeholders invest in domestic critical minerals and energy transition initiatives, we support efforts to turn subsurface data into actionable information to determine resource value and profitable extraction techniques while meeting rigorous mining regulations for environmental protection.
Mining is one of the most highly regulated and environmentally sensitive industries in the U.S. At the same time, federal and state priorities emphasize the strategic importance of domestic rare earth element and critical mineral production, both from conventional and, increasingly, unconventional resources. Learn more here, or contact one of our National Experts!
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